Strut mount

ABSTRACT

The present invention provides a strut mount bolted to a curved outer cylinder attachment plate ( 6 ) without enlarging a bolt hole, by inserting a cylindrical portion ( 13 ) of a caulking nut ( 5 ) into a nut attachment hole ( 11 ) of an attachment piece ( 10 ) of an outer cylinder ( 2 ) and pressurizing and diminishing in diameter the circumference of the nut attachment hole ( 11 ) to caulk and stick the nut attachment hole ( 11 ) and the caulking nut ( 5 ).

FIELD OF THE INVENTION

[0001] This invention relates to a strut mount disposed at an attachmentportion of a buffer to a vehicle.

DESCRIPTION OF THE RELATED ART

[0002] In general, in a suspension system of an automobile, etc., aso-called strut mount is disposed at an attachment portion of a bufferto a vehicle body, in order to control vibration, etc. propagated fromwheels to the vehicle body.

[0003]FIG. 6 shows an example of the strut mount. The strut mountcomprises an inner cylinder 101 in which a piston rod of the buffer isfixed, an outer cylinder 102 attached to the vehicle body, and a rubberelastomer 103 interposed between the inner and outer cylinders to dampeninput vibration, and a bolt 106 inserted into a bolt hole 105 thereoffrom below is press fitted and secured to an attachment piece 104 of theouter cylinder 102. With the bolt 106 lifted up so as to insert into abolt hole 108 of the vehicle body's outer cylinder attachment plate 107from below and a nut tightened from above the outer cylinder attachmentplate 107, the strut mount will be attached to the vehicle body only byattachment working from above.

[0004] In order to raise rigidity and improve running properties, thestrut mount shown in FIG. 6 is constructed so that the attachment piece104 of the outer cylinder 102 and the outer cylinder attachment plate107 of the vehicle body are curved in the form of a sphere, and thateach bolt 106 press fitted and secured to the attachment piece 104 isoriented toward the inclined direction, respectively, against thedirection of movement (perpendicular) when the strut mount is lifted up.For that purpose, the bolt hole 108 on the outer cylinder attachmentplate 107 is made larger so that the bolt 106 oriented toward theinclined direction can be inserted.

[0005] However, when the bolt hole is large, it is apprehended thatthere occur problems related to bolt tightening such as looseness.Therefore, a means of inserting the bolt, without making the bolt holelarger, and tightening the bolt only by operations from above ispursued.

DISCLOSURE OF THE INVENTION

[0006] The present invention has been made in view of the subjectsdescribed above, and it is an object of the invention to provide a strutmount intended to insert a bolt, without making the bolt larger, andtighten an attachment piece of an outer cylinder at the underside of avehicle body's outer cylinder attachment plate, with a bolt, only byoperations from above, by providing a nut at the underside of the outercylinder attachment piece and screwing the bolt into the nut from upsidethe outer cylinder attachment plate of a vehicle body.

[0007] When providing the nut for the attachment piece of the outercylinder, a technique that a small hole is drilled at the prescribedposition on the attachment piece of the outer cylinder, a burr is formed(burring working) downwardly around the circumferential edge of the holeas a cylindrical portion, and an inner circumferential surface of thecylindrical portion is tapped and cut as screw threads to serve as anut, also comes to mind. However, such technique makes its workingdifficult and complicated. Furthermore, in order to elongate the nut ofa given diameter and cut the required number of screw threads, it isnecessary to thicken the outer cylinder, with the result that the weightof the components grows heavier.

[0008] Otherwise, as for the method of welding a nut on the underside ofthe attachment piece of the outer cylinder, in order to avoiddeterioration of rubber elastomer due to welding heat, it is necessaryto weld the nut before working the strut mount or to escape welding heatby masking around the nut of the attachment piece, whereby making thestrut mount working difficult and complicated.

[0009] Accordingly, the present invention adopts a nut securing means ofmaking the thickness of the outer cylinder thinner to lightweight thecomponents, without causing difficult and complicated working, andcapable of maintaining the durability of rubber elastomer, by caulkingand securing the nut on the underside of the attachment piece of theouter cylinder.

[0010] When caulking and securing the nut to the attachment piece of theouter cylinder, either upsetting on the nut side or diminishing indiameter the nut attachment hole of the outer cylinder can be adopted.

[0011] In case of upsetting on the nut side, the nut attachment hole isdrilled on the attachment piece of the outer cylinder, on the otherhand,a cylindrical portion is provided continuously from the nut portion forthe caulking nut: the cylindrical portion is inserted into the nutattachment hole from the underside of the attachment piece of the outercylinder; after that, when the cylindrical portion is upset and caulkedand secured to the nut attachment hole, an outer circumferential surfaceof the cylindrical portion is stuck fast to an inner circumferentialsurface of the nut attachment hole, thus sticking the nut on theunderside of the attachment piece of the outer cylinder.

[0012] In case where the nut attachment hole is diminished in diameter,with the cylindrical portion of the caulking nut inserted into the nutattachment hole from the underside, by pressurizing the circumference ofthe nut attachment hole from the direction square to the plate surfaceof the attachment piece of the outer cylinder, the inner circumferentialsurface of the nut attachment hole is stuck fast to the outercircumferential surface of the cylindrical portion to caulk and stickthe nut on the underside of the attachment piece of the outer cylinder.

[0013] At this time, provided that the outer circumferential surface ofthe cylindrical portion of the caulking nut is corrugated, an extra wallsurrounding the nut attachment hole cuts into the corrugated outercircumferential surface of the cylindrical portion as the nut attachmenthole is diminished in diameter, the extra wall acts as a steady rest torestrain the caulking nut from turning together with the bolt.

[0014] When the attachment piece of the outer cylinder and the outercylinder attachment plate of a vehicle body are curved in the form of aspherical surface, the aforementioned means may appropriately be usedfor a strut mount. Where the form of a spherical surface denotes acurved surface constituting a part of a sphere.

BRIEF DESCRIPTION OF THE DRAWINGS

[0015]FIG. 1 is a sectional view of a strut mount of the presentinvention.

[0016]FIG. 2 is a perspective view of a caulking nut of the inventionshowing a cylindrical portion being diminished in diameter.

[0017]FIG. 3 is a sectional view showing the state of attachment of thecaulking nut of FIG. 2.

[0018]FIG. 4 is a perspective view of a caulking nut showing anotherembodiment.

[0019]FIG. 5 is a sectional view showing the state of attachment of thecaulking nut of FIG. 4.

[0020]FIG. 6 is a sectional view of conventional strut mount.

BEST MODE FOR CARRYING OUT THE INVENTION

[0021] Best mode for carrying out the strut mount of the presentinvention will be hereinafter described with reference to the drawings.FIG. 1 is a sectional view of the strut mount of the invention. FIG. 2is a perspective view of the caulking nut used for the presentembodiment of the invention. FIG. 3 is a sectional view of the caulkingnut stuck to the nut attachment hole of the outer cylinder attachmentpiece.

[0022] The strut mount comprises an inner cylinder 1 to which a pistonrod of a buffer is fixed, an outer cylinder 2 attached to the vehiclebody side, a rubber elastomer 3 in the form of a ring interposed betweenthe inner and outer cylinders 1, 2 to dampen input vibration, the outercylinder 2 being fastened on the outer cylinder attachment plate 6curved in the form of upwardly convex sphere on the vehicle body side bythe bolt 4 and the caulking nut 5.

[0023] The inner cylinder 1 is a tubular steel product disposed on theinside of the rubber elastomer 3, and at its lower extremity an inwardlyannular flange 7 is formed in the direction square to the axialdirection. Inside of the inner cylinder 1 there is space for fixing thepiston rod that inserts through inside the flange 7 from the undersideby a nut, etc. The inner circumferential surface of the rubber elastomer3 is vulcanization adhered to the outer circumferential surface of theinner cylinder 1. A steel tubular bound bumper seat 8 is disposed on theunderside of the inner cylinder 1, at the upper extremity thereof anannular flange 9 formed inwardly is stacked on the flange 7 of the innercylinder 1, where by the inner cylinder 1 is integral with the boundbumper seat 8.

[0024] The outer cylinder 2 is a tubular steel product disposed nearlyconcentrically with the inner cylinder 1 so as to cover the innercylinder 1 from outside and embedded in the rubber elastomer 3. At theupper extremity of the outer cylinder 3, a curved annular attachmentpiece 10 is formed so as to be outwardly in the direction square to theaxial direction and become higher on the inside. The attachment piece 10is tightened on the underside of the outer cylinder attachment plate 6of the vehicle body by the bolt. The portion of the attachment piece 10to be tightened by the bolt, where a nut attachment hole 11 is drilled,is projected outside of the rubber elastomer 3. A caulking nut 5 isstuck to the nut attachment hole 11.

[0025] The caulking nut 5 comprises a nut portion 12 disposed on theunderside of the attachment piece 10 and a cylindrical portion 13inserted into the nut attachment hole 11 from the underside. On theinner circumferential surface of the nut portion 12 and the cylindricalportion 13, screw threads are cut continuously, wherein the bolt 4 isscrewed. The caulking nut 5 is stuck to the nut attachment hole 11, thecircumference of which, on the attachment piece 10, is pressurized andcaulked, which is then diminished in diameter. For the purpose of makingharder than the attachment piece 10, the caulking nut 5 is a hardenedsteel product.

[0026] Having larger diameter than the nut attachment hole 11, the nutportion 12 gets caught in the circumferential edge of the nut attachmenthole 11 so as not to slip through and come out the attachment piece 10upwardly. A groove 14 is made around the cylindrical portion 13 abovethe nut portion 12, so extra wall of the attachment piece 10 cuts intothere when pressurizing the circumference of the nut attachment hole 11.

[0027] The cylindrical portion 13 has an outside diameter enough to beinserted into the nut attachment hole 11, and its outer circumferentialsurface is corrugated so that the extra wall of the attachment piece 10cuts into the cylindrical portion 13 when pressurizing the circumferenceof the nut attachment hole 11. The closer to the base extremity side(lower side) the cylindrical portion 13 reaches, the deeper thecorrugation 15 on the outer circumferential surface is formed. The extrawall being cut into is intended to restrain the caulking nut 5 fromslipping through downward.

[0028] Next, the procedure of attaching the strut mount to the outercylindrical attachment plate 6 of a vehicle body is described below.First, the cylindrical portion 13 of the caulking nut 5 is inserted frombelow into the nut attachment hole 11 of the strut mount assembled, andthen the circumference of the nut attachment hole 11 of the attachmentpiece 10 is pressurized and caulked from above.

[0029] At this time, the nut attachment hole 11 is diminished indiameter, and the inner circumferential surface thereof is stuck fast tothe cylindrical portion 13. Further, the extra wall of the attachmentpiece 10 cuts into the corrugation 15 on the outer circumferentialsurface of the cylindrical portion 13, whereby forming a steady restthat restrains the bolt 4 from turning together with the caulking nut 5,with the result to secure predetermined turning torque. Being made ofhardened steel, the caulking nut 5 will not be deformed.

[0030] With the strut mount lifted up so that the inner cylinder 1passes through an opening 16 of the outer cylinder attachment plate 6 ofthe vehicle body, and also with the underside of the bolt hole 17 on theouter cylinder attachment plate 6 of the vehicle body aligned with thebolt hole of the caulking nut 5, the bolt 4 inserted vertically into theplate surface from above the outer cylinder attachment plate 6 through awasher 18 is screwed into the caulking nut 5 and the attachment piece 10of the outer cylinder 2 is bolted to the outer cylinder attachment plate6 of the vehicle body, then attachment of the strut mount is completed.

[0031] According to the configuration described above, since the bolt 4can be inserted perpendicularly to the plate surface even when the outercylinder attachment plate 6 of the vehicle body is curved, it is notnecessary to make the bolt hole 17 of the outer cylinder attachmentplate 6 larger, and problems such as looseness can be dissolved.Further, since the attachment piece 10 is caulked to stick the caulkingnut 5, it is not necessary to thicken the attachment piece 10 of theouter cylinder 2 just like in the case of burring working, so that theweight of the components can be reduced. Besides, because the nut is notwelded, post working can easily be performed even after vulcanizationforming of the rubber, labor saving during operations.

[0032]FIGS. 4 and 5 show other embodiments of the caulking nut. FIG. 4is a perspective view of the caulking nut when upsetting the cylindricalportion. FIG. 5 is a sectional view of the caulking nut stuck to the nutattachment hole by upsetting the cylindrical portion.

[0033] The caulking nut 19 comprises a nut portion 20 disposed on theunderside of the attachment piece 10 and a cylindrical portion 21 thatis inserted into the nut attachment hole 11 from the underside. Thecaulking nut 19 is caulked and secured to the nut attachment hole 11 bypressurizing and upsetting the cylindrical portion 21 outwardly. For thepurpose of making harder than the attachment piece 10, the caulking nut19 is a hardened steel product.

[0034] Having larger diameter than the nut attachment hole 11, the nutportion 20 gets caught in the circumferential edge of the nut attachmenthole 11 so as not to slip through and come out of the attachment piece10 upwardly. On the inner circumferential surface of the nut portion 20,screw threads are cut, wherein the bolt 4 is screwed.

[0035] The cylindrical portion 21 has an outside diameter enough to beinserted into the nut attachment hole 11, and its inside diameter islarger than that of the nut portion 20 so as not to deform the screwthreads of the nut portion 20 when being caulked. Having a chamfering 22on the above side of the circumferential edge of the nut attachment hole11, the upsetting upper extremity of the cylindrical portion 21 isgotten caught so as not to slip through and come out of the caulking nut19 downwardly.

[0036] In the configuration described above, when attaching the caulkingnut 19 to the attachment piece 10, the nut attachment hole 11 is drilledon the attachment piece 10 of the outer cylinder, the cylindricalportion 21 integral with the nut portion 20 is provided for the caulkingnut 19, and then the cylindrical portion 21 is inserted into the nutattachment hole 11 from the underside of the outer cylinder attachmentpiece 10. After that, when the cylindrical portion 21 is upset and thenis caulked and secured to the nut attachment hole 11, the outercircumferential surface of the cylindrical portion 21 is stuck fast tothe inner circumferential surface of the nut attachment hole 11, wherebythe nut 19 can be stuck to the underside of the outer cylinderattachment piece 10.

Industrial Applicability

[0037] According to the present invention, it will be obvious from thedescription above that rigidity can be raised to improve runningproperties, because the outer cylinder attachment plate can be curved bythe use of the caulking nut stuck to the underside of the attachmentpiece of the outer cylinder, without enlarging the bolt hole of theouter cylinder attachment plate of the vehicle body.

[0038] Furthermore, cost reduction can be accomplished by thinning theplate thickness to lightweight the products and also labor saving duringoperations. Accordingly, it is an object of the invention to provide anoptimum strut mount as a suspension system for automobile and the like.

What is claimed is:
 1. A strut mount an attachment piece of an outercylinder of which is bolted to the underside of an outer cylinderattachment plate of a vehicle body: wherein, both the attachment pieceof the outer cylinder and the outer cylinder attachment plate of thevehicle body are connected by tightening a bolt fastened to a nut, whichis caulked and secured on the underside of the attachment piece of theouter cylinder, and which is screwed from above the outer cylinderattachment plate of the vehicle body.
 2. The strut mount as set forth inclaim 1, wherein the nut is a caulking nut with a cylindrical portionthat is inserted into the nut attachment hole drilled on the attachmentpiece of the outer cylinder, and the caulking nut with the upsettingcylindrical portion is stuck to the attachment piece of the outercylinder.
 3. The strut mount as set forth in claim 1, wherein the nut isa caulking nut with a cylindrical portion that is inserted into the nutattachment hole drilled on the attachment piece of the outer cylinder,and the caulking nut is caulked and secured to the attachment piece ofthe outer cylinder by pressurizing the circumference of the nutattachment hole from the direction square to the attachment piece platesurface of the outer cylinder and diminishing in diameter the nutattachment hole.
 4. The strut mount as set forth in claim 3, wherein theouter circumferential surface of the cylindrical portion of the caulkingnut is corrugated, an extra wall surrounding the nut attachment holecuts into the corrugated outer circumferential surface of thecylindrical portion as the nut attachment hole is diminished indiameter, the extra wall acting as a steady rest to restrain thecaulking nut from turning together with the bolt.
 5. The strut mount asset forth in claims 1 to 4, wherein the attachment piece of the outercylinder and the outer cylinder attachment plate of a vehicle body arecurved in the form of a spherical surface.